Nephrops in Division 7f,g,h (Celtic Sea, FU20-21), Demersal otter trawl
- Content last updated
- 31 October 2019
- Norway lobster (Nephrops norvegicus) in divisions 7.g and 7.h, functional units 20 and 21 (Celtic Sea)
- Stock Status
Nephrops in Division 7f,g,h (Celtic Sea, FU20-21; Labadie, Jones and Cockburn) has been scored low risk. The stock size in relation to MSY Btrigger is unknown though it is above long term average, and the harvest rate (F) is below FMSY.
The risk score was evaluated using the RASS scoring guideline’s data-limited approach where the above average abundance and the low (at 1.7%) harvest rate (percentage of the stock caught every year) which is less than one third that which is considered to correspond with Maximum Sustainable Yield (FMSY) for this stock.
Nephrops in Division f,g,h (Celtic Sea, FU20-21) has been scored moderate risk. Whilst the Functional Unit is assessed annually as a data-limited stock by ICES, the TAC is set for the Sub-area 7 as a whole, which could lead to uncontrolled increases in fishing effort in individual Functional Units.
There is provision within the current Multi Annual Plan for the Western Waters to introduce measures to conserve individual Nephrops Functional Units if required. However, a full set of reference levels is not available for this Functional Unit at present, so it could be difficult to define whether these measures should be introduced.
Surveillance of enforceable measures can be considered moderately effective with adequate compliance and enforcement.
The bycatch risk of this fishery has been scored high risk. This is because the overall bycatch and discard rates are high in Nephrops trawls due to the small cod end mesh requirements of the target species and due to relatively high discard rates of Nephrops themselves. There is also a moderate risk to Protected, Endangered and Threatened (PET) species; these are likely to be impacted by the fishery but have high survival rates. However, measures to reduce bycatch and discards in these fisheries have been the subject of much research over the years, resulting in technical measures which improve selectivity, which in turn have been implemented as statutory requirements.
The habitat risk of this fishery has been scored a high risk. This is because Nephrops trawlers target specific habitats containing burrowing mud communities. Changes in the biodiversity of these areas have been associated with trawling. There is a process in place under the OSPAR convention and UK Marine Acts to avoid adverse impacts through the designation of Marine Protected Areas of which two are designated within these FUs, one containing area that may be vulnerable to the gear.